5. Glossary

Spectral attenuation

Characterizes signal attenuation during propagation (Beer-Lambert law). It is expressed per unit length at a given wavelength, e.g. 0.2 dB/km at 1.55 µm. The transmission of silica fibers is limited by Rayleigh scattering (in 1/λ ⁴ ) from UV to near IR, and by IR absorption beyond.

Biophotonics

A new field of science that combines biology and photonics, and concerns the use of light to analyze and modify biological objects.

BPM; Beam Propagation Method

A technique introduced in the 70s to simulate light propagation in optical waveguides whose parameters vary slowly (fibers). BPM is based on approximate differential equations. This unidirectional model involves only a first-order derivative in the variable...